Taximeters



Nov- 29, 19 s. G. MARSHALL 2,962,210

TAXIMETERS Filed Aug. 21, 1956 73 W er lNVENTO Q Arm/v Z3 United States Patent" TAXIMETERS Sydney G. Marshall, Iver Heath, England, assignor. to Bell Punch Company Limited; London, England; a British company FiledrAiugcZl, 1956, SenNo; 605,295;

Claims priority, applicationGr-eat BritainSept. 26, 1955 2-Claimsv (Cl. 235-30).

This inventionrelatesto taximeters and hasfor, its object to provide therein a simple-and reliable device for protecting those interior parts of a taximeter which are operated by the flag, and similarly the fiag itself and its operative connection to said parts, from strain or other damage in the event of there arising for any reason within the meter a resistance to movement of said parts in excess of that which is normal in the use of the meter.

According to the invention, there is provided a taximeter having between the boss of the flag arm and that part of the interior mechanism of the meter which is operated by the flag an overload release coupling through which the movement of the flag is transmitted to said part.

By an overload release coupling is meant a coupling adapted automatically to yield to an overload above a predetermined magnitude in the sense that whilst under normal load conditions the driving and driven elements of the coupling are in positive torque-transmitting relation to one another, under conditions of overload, said overload being above a predetermined magnitude, the driving element of the coupling automatically frees itself from positive-torque transmitting connection with the driven element so as to be free to move under the torque transmitted to it without necessarily imparting corresponding movement to the driven element.

As will be appreciated, the present invention provides an arrangement in which, in the event of there arising in the meter for any reason at all a resistance to movement of the flag operated parts of the meter, said resistance being greater than that which is normal in the use of the meter, the flag, whilst it can still be rotated, will virtually slip relatively to said parts of the meter, with the result that these will not be operated by the movement of the flag.

A preferred form of the invention is one wherein the overload release coupling intervenes between the boss of the flag arm and the flag spindle, in which case the coupling may conveniently comprise a roller freely revoluble on a pin carried by the flag spindle in fixed relation thereto, said pin being disposed with its axis transverse to the axis of the spindle; a rotary cam coaxial and fast with the boss of the flag arm, said cam having a freedom for movement relatively to the flag spindle along the axis thereof and said cam having two oppositely handed cam tracks directed axially of the cam and extending in respectively opposite directions from a notch therein intervening centrally between the tracks at the bottom thereof; and a yielding control for the cam tending always to maintain the latter in engagement with the roller against the reaction of the flag spindle, the arrangement being one in which under normal (no-overload) conditions of operation of the flag the roller is firmly seated in the notch in torgue-transmitting relation to the cam while under overload conditions of operation of the flag the notch, upon operation of the flag in either direction, disengages from the roller and the relative cam track (according to the direction of rotation of the flag) rides thereon.

The invention will nowbe further described with refere".

ence to the accompanyingdrawings, whichaillustratethe foregoing preferred form of the invention, purely by way of example.

In these drawings:

Figure l is a-front view of a taximeter of conventional design; and

Figures 2 and 3 are fragmentary sectional views through the flag spindle of the meter and its connection to parts of' the meter which are operated, by the flag, the view showing the overload release coupling of the invention (a) under normal load conditions (Figure 2) and (b) under overload conditions (Figure 3).

Like reference numerals are applied to like parts. in the various figures.

The arrangement shown is one in which the fiag 1, which may be of the plain type with embossed letters or of the internally illuminated type, is secured to a sleeve 2. The sleeve 2 is coaxial with the taximeter control shaft or flag spindle 3 and is freely revoluble thereon, said sleeve having a freedom for axial movement along the spindle in the manner and in the circumstances later described.

The flag is located in its correct relationship with the flag spindle 3 by a roller 4 freely revoluble on a pin 5 carried by the flag spindle in fixed relation thereto. As shown, said pin is disposed with its axis transverse to the axis of the flag spindle and is carried in a head 6 on the end of the flag spindle.

The roller 4 engages normally (i.e. under normal load conditions in-the use of the meter) in an arcuate notch 7 intervening centrally between two oppositely handed cam tracks 8 and 9 directed axially of a rotary cam 10 coaxial and fast with the boss 11 of the flag arm 12. The cam tracks 8, 9, which are of spiral form, extend in respectively opposite directions from the notch 7, which therefore intervenes centrally between them at the bottom of the tracks.

The sleeve 2 which, through the intermediary of the cam, is coaxial and fast with the boss 11 of the flag arm, has at its inner end a free revoluble fit within the bore of a case bushing 13 having at the inner end thereof a cylindrical bearing 14 through which the flag spindle extends with a free revoluble fit, the flag spindle, the sleeve 2 and the bearing 1-4 being coaxial with one another.

Housed within the bore of the case bushing 13 in interposition between the inner end of the sleeve 2 and the bottom of said bore is a compression spring 15 functioning to press the sleeve 2 outwardly, thereby maintaining the roller 4 in normal, torque-transmitting engagement with the cam 7, the roller being in seated position within the notch 7.

It will be understood, therefore, that the arrangement described and illustrated in the drawings is one in which under normal (no overload) conditions the roller 4 is firmly seated in the notch 7 in torque-transmitting relation to the cam, while under overload conditions of operation of the flag the notch 7, upon operation of the flag in either direction, automatically disengages from the roller, the relative cam track 8 or 9 (according to the direction of rotation of the flag) riding thereon. It will also be appreciated that the arrangement is further one in which, upon release of the flag, following movement to a position in which the cam track 8 or 9 is riding on the roller 4, the flag will automatically return to normal position again with respect to the flag spindle, due to the action of the spring 15 forcing the cam 10 against the roller 4, thus creating a strong turning movement on the sleeve which returns the flag, as stated, to its normal location relatively to the flag spindle.

The invention is capable of considerable variation as regards constructional details. For example the overload release coupling may take any other convenient form than that described with reference to the drawings, although it may be remarked that the form described is generally speaking a preferred form for the purposes of the invention, owing to its simplicity and reliability of action. Also the yielding control for the cam of the coupling may take any other form than that employed in the particular arrangement described and shown in the drawings. All such possible variations are to be understood as within the scope of the appended claims.

, What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. A taximeter comprising a spindle, a flag arm journaled on the spindle for rotation relative thereto, and means coupling the flag arm and spindle for rotation together about the axis of the spindle, said means comprising a cylindrical cam coaxially supported about the spindle for rotation relative thereto, said flag arm being afiixed to said cam, a cam follower arranged on the spindle, and resilient means engaged between the spindle and cam stressing the follower against the cam.

References Cited in the'file of this patent UNITED STATES PATENTS 1,469,932 Adams Oct. 9, 1923 1,631,196 Froesch June 7, 1927 1,786,745 Gehlen Dec. 30, 1930 2,102,002 Hill Dec.' 143.1937 2,144,769

Melmer Ian. 24, 1939 

